It's thought the argument was sparked by Paul saying Liam would only ever be known as 'that guy from the band'.

Speaking to The Sun , one onlooker said: “Liam was shouting, ‘How dare you say that? You’re so f***ing rude’.

“He was obviously very angry and was jabbing his finger in Paul’s direction. And Paul was giving as good as he got back.

“Neither of them were making any effort to hide the row, and were very loud. They were drinking in the area outside the pub and fellow drinkers were sticking their head out the door to see what the hell was going on.

“It looked at one point like it was going to come to physical blows.”

Thankfully, Liam was spotted walking away form the scene before things escalated, but by that point the drama had already caused a commotion.

Not that this is the first time he's suffered a public slanging-match with a relative, of course.

His on-going feud with Noel has become the stuff of rock-n-roll legend, with the pair using social media and the press to insult each other.